Anticreep construction for projectiles detonated on impact



Feb. 20, 1962 H. R. MICHAELS 3,021,787

ANTICREEP CONSTRUCTION FOR PROJECTILES DETONATED ON IMPACT Filed March 15, 1957 INVENTOR.

HENRY R. MICHAELS 1 United States Patent 3,021,787 ANTICREEP CONSTRUCTION FOR PROJECTELES DETONATED 0N IMPACT Henry R. Michaels, Mercer, Wis., assignor to tewart- Warner Corporation, Chicago, Ill., a corporation of Virginia Filed Mar. 15, 1957, Ser. No. 646,497

1 Claim. (Cl. 102-73) My invention relates generally to projectiles detonated upon impact, and more particularly to means for preventing creep of the firing pin as the projectile is subjected to deceleration in the latter portion of its trajectory, so as to assure detonation upon direct or grazing impact of the projectile with the target, or with the terrain near the target.

In projectiles in which the detonation is accomplished by means of a firing pin which is operated by the force of inertia of the firing pin opposed by a coil spring, or similar spring, and in which the resistance to relative movement of the firing pin toward the detonator cap is opposed by such spring, there is a tendency, as projectile decelerates, for the firing pin to creep toward the detonator cap, so that upon impact with the target, or particularly with grazing impactwith the adjacent terrain, such spring may be compressed to such an extent that the deceleration, resultant from such impact, may be insufiicient to cause the firing pin to strike the detonator and cause brisance thereof.

It is thus an object of the invention to provide resilient means to hold the firing pin of a projectile in ineffective position when subjected only to normal forces of momentum or deceleration during the retarding of the projectile in its normal trajectory, but to provide a sudden release of the firing pin when the projectile is more suddenly decelerated, as when striking or grazing the target or'adjacent terrain. This object is accomplished by providing means for holding the firing pin against relative movement toward the detonator when the projectile is decelerating normally during the latter portion of its trajectory, and releasing the firing pin for effective engagement with the detonator when such normal deceleration is exceeded, as when the projectile is greatly decelerated by striking or grazing the tan-get or adjacent terrain.

The invention is shown, to enlarged scale, in the accompanying drawing as comprising a shell or fuze body having a bore 12 in which a cup-like housing 14 for a firing pin 16 is pressed. The firing pin 16 has a generally cylindrical portion 18 guided for axial movement in the housing 14 and having an enlarged diameter head 20 provided with a pointed forwardly projecting point 22 which is adapted, upon impact, to strike a detonator 24, which, upon detonation, through a Cordeau or similar explosive train, tires the main charge of the projectile.

The firing pin 16 is normally held against movement toward the detonator 24 by a leaf spring 26, one end of which is anchored to the rear end of the housing 14 by a swaged flanged bushing 28, and the'other end of which projects into a longitudinal slot 29 in the firing pin 16, and has a deformed detent portion 39 which engages an annular groove 32 formed in the firing pin part 18. This detent is resilient but provides a sufficient holding force to prevent the firing pin to advance toward the detonator 24 as the projectile decelerates, but at the same time is sufiiciently yieldable, so that upon deceleration of the projectile either upon direct or grazing impact, the firing pin will be released, and due to its inertia, move rapidly toward the detonator, and by forceful impact against it, cause brisance thereof.

While I have shown and described a preferred embodiment of my invention, it will be apparent that numerous variations and modifications thereof may be made without departing from the underlying principles of the invention. I therefore desire, by the following claim, to include within the scope of the invention all such variations and modifications by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim:

An inertia operated firing pin assembly for cooperation with a fuze having a detonator comprising a cylindrical housing having one open and one closed end; a firing pin having a reduced cylindrical portion slidable in the housing, a larger diameter portion outside the housing, and a point on the larger portion for engagement with the detonator; the reduced portion defining a slot longitudinally on its outer periphery tapering as it progresses from an intermediate portion to the outer end; the reduced portion defining a circumferential groove intermediate the ends of the slot; a narrow elongated fiat spring rigidly secured to the closed end of the housing, received in the slot, and having a V-shaped section held in the groove under tension to hold the firing pin from movement toward the detonator until the fuze is decelerated rapidly incident to grazing or direct impact with a target or terrain.

References Cited in the file of this patent UNITED STATES PATENTS 320,210 Bennett June 16, 1885 1,687,341 Lukens Oct. 9. 1928 1,687,484 Van Essen Oct. 9, 1928 2,378,626 Fanger June 19, 1945 2,436,396 McCaslin Feb. 24, 1948 3,021,787 Patented Feb. 20, 1962 

